In the ideal case, the charging holes in the roof of a coke oven are equidistantly spaced and aligned in the travel direction of the coal-charging larry cart. The real conditions on a coke oven regularly deviate from this ideal case. In particular in older coke ovens, the position deviations of the charging holes in both axes are frequently ±50 mm, which may not be compensated for by centering aids typical in the art. This has the result that the charging hole lids may no longer be lifted automatically and later replaced automatically into the charging-hole jamb, and the charging-hole jamb cleaning also no longer functions satisfactorily. In coking-plant operation, interruptions arise in the automatic sequence of the coal-charging larry cart in this way and personnel-intensive interventions are necessary. Furthermore, charging-hole jambs on the roof must frequently be realigned, so that lid lifters and jamb cleaners may operate properly. Significant maintenance costs thus arise for the coking-plant operation.
A system that combines apparatuses for lifting lids out of charging holes and for cleaning the charging-hole jambs with a coal-charging apparatus having a horizontal conveyor screw with an outlet-side charging telescope to form an operating unit that is set up to be adjustable in two axes on the underside of a coal-charging larry cart is known from EP 1 293 552 B1. In these known systems, the horizontal conveyor screw is suspended on an positionable carriage that is guided on tracks on the underside of the coal-charging larry cart. The horizontal conveyor screw can move transversely to the tracks on profiled elements of the positioning carriage. The cover lifter and the jamb cleaner may adapt to the particular position of the charging holes in the roof of the coke oven by a dual-axis positioning of the operating unit. Using the known configuration, the lift magnet of the cover lifter and the cleaning head of the jamb cleaner may be brought into an operating position in which they align with the charging hole in the roof of the coke oven. However, this known configuration requires large vertical space below the coal outlet on the underside of the coal-charging larry cart, because the operating unit is attached on the intake-side end of the horizontal conveyor screw using a compensator that must make up for horizontally positioning the operating unit relative to two axes. This installation space is not always available. The known apparatus is not suitable or is only suitable with restrictions for retrofitting to existing coking installations.